void setup() 
{
pinMode(3, OUTPUT); 
pinMode(4, OUTPUT); 
pinMode(5, OUTPUT);
}
void loop()
 {
 digitalWrite(3, HIGH); 
 digitalWrite(4, HIGH);
 digitalWrite(5, LOW);
 delay(3000);
 digitalWrite(3,LOW);
 digitalWrite(4, HIGH);
 digitalWrite(5, HIGH);
 delay(4000);
 digitalWrite(3, HIGH);
 digitalWrite(4, LOW);
 digitalWrite(5,HIGH);
 delay(5000);
}
//  r     y
//y    g
//g    r